It's more than enough. Dude, your video card is ANCIENT ('04/'05), probably like the rest of your pc. 256mb video ram!? I suppose you have 1 core cpu, right? and how much RAM? IMO If you eventually run the game I can't see you getting more than 10-15 fps (at best).

Could you post a screenshot of your campaign map and maybe screenshot with the message (or write the exact text of the message)? You give so little information that we don't really know what are you talking about.